INICET Dermatology Previous Year Questions (2018–2026)

The correct answer is 1-a, 2-b, 3-c, 4-d.

The Nikolsky sign (skin shears off with lateral pressure) reflects loss of epidermal cohesion. A true positive Nikolsky sign occurs in pemphigus vulgaris, where intraepidermal acantholysis splits the epidermis (1-a). The pseudo-Nikolsky sign is seen in Stevens-Johnson syndrome / TEN, where full-thickness epidermal necrosis lets a shearing force extend the blister (2-b). A false (negative) Nikolsky is characteristic of bullous pemphigoid, a subepidermal blister with an intact epidermis (3-c). The cerebriform tongue (sulci-and-gyri pattern from papillary hyperplasia) is a clue to pemphigus vegetans (4-d).

Why the other options are wrong:

• 1-c, 2-b, 3-a, 4-d: swaps pemphigus vulgaris and bullous pemphigoid - pemphigoid is Nikolsky-negative, not positive.
• 1-a, 2-b, 3-d, 4-c: wrongly links false Nikolsky to pemphigus vegetans and cerebriform tongue to bullous pemphigoid.
• 1-d, 2-c, 3-b, 4-a: mismatches almost every pair (e.g., positive Nikolsky is not pemphigus vegetans).

High-Yield Facts:

• Positive Nikolsky = intraepidermal acantholysis (pemphigus vulgaris).
• Pseudo-Nikolsky = full-thickness necrosis (SJS/TEN).
• Bullous pemphigoid is Nikolsky-negative (subepidermal blister).
• Cerebriform tongue points to pemphigus vegetans.

Figure 1: Pemphigus vulgaris - flaccid blisters rupture into painful crusted erosions, with a positive Nikolsky sign.

Figure 2: Pemphigus vulgaris histology - suprabasal acantholytic blister with a 'tombstone' layer of retained basal keratinocytes.

Correct Answer: 1 and 3 only

Clinical Reasoning:

1. Regeneration (Statement 1 is TRUE):

• The skin appendages (hair follicles, sebaceous glands, and sweat glands) are invaginations of the epidermis deep into the dermis.
• They contain epithelial stem cells (specifically in the "bulge" region of the hair follicle). In the event of superficial trauma or burns (partial-thickness) where the surface epidermis is destroyed, re-epithelialization occurs via the migration of these stem cells from the appendages upwards to the surface.

2. Embryological Origin (Statement 3 is TRUE, Statement 4 is FALSE):

• Epidermis: Derived from the Surface Ectoderm.
• Dermis & Hypodermis: Derived from the Mesoderm (specifically paraxial mesoderm/dermatomes for the dorsal skin and lateral plate mesoderm for ventral skin), not the endoderm.
• Melanocytes: Derived from the Neural Crest (neuroectoderm).

3. Stratum Corneum (Statement 2 is FALSE):

• The Stratum Corneum is indeed the outermost layer, but it consists of dead, anucleated corneocytes (flattened squames filled with keratin), not viable cells. The term "cellular layer" in this context typically implies living, nucleated cells (the outermost living layer is the Stratum Granulosum).

Correct Answer: 2, 3 and 4 (Skin atrophy, Acneiform eruptions, Hypertrichosis)

Clinical Reasoning:

Local Side Effects of Topical Corticosteroids:

Topical steroids are the mainstay of dermatological therapy, but their prolonged use, especially of high-potency agents or on sensitive areas (face, flexures), leads to specific local adverse events:

• Skin Atrophy (Statement 2): This is the most common side effect. Steroids inhibit fibroblast proliferation and collagen synthesis, leading to thinning of both the epidermis and dermis. This manifests as transparency of the skin, fragility, and striae (stretch marks).
• Acneiform Eruptions (Statement 3): Often referred to as "Steroid Acne." Unlike vulgaris, these lesions are typically monomorphic (papules and pustules in the same stage of development) and lack comedones initially. They commonly occur on the chest or back.
• Hypertrichosis (Statement 4): Increased hair growth (hirsutism/hypertrichosis) at the site of application is a well-documented side effect.
• Other common local effects: Telangiectasia (visible blood vessels), Striae distensae (irreversible), Hypopigmentation (lightening of skin), and predisposition to secondary bacterial or fungal infections (Tinea incognito).

Why Statement 1 is Incorrect:

• Blue Discoloration: Corticosteroids cause hypopigmentation (whitening/lightening) by inhibiting melanocyte function, not blue discoloration.
• Blue-black or slate-grey discoloration is characteristic of drugs like Minocycline, Amiodarone, or conditions like Ochronosis (associated with Hydroquinone use), but not corticosteroids.